Carboxy vinyl polymer and sulfonated alkyl acrylamide polymer mobility control agent and process

ABSTRACT

Carboxy vinyl polymer (CVP) (Carbopol 961) when dissolved with sulfonated alkyl acrylamide polymer, increases screen factor and provides enhanced supplemented recovery of oil.

Norton et al.

fies met July 23, 1974 Assignee:

US. Cl 166/305 R, 166/275, 252/855 D Int. Cl E2lb 43/16 Field of Search 166/275, 274, 273, 305 R;

[56] References Cited UNITED STATES PATENTS 2,798,053 7/1957 Brown 252/89 X 3,679,000 7/l972 Kaufman 166/275 X Primary ExaminerErnest R. Purser Assistant Examiner.lack E. Ebel Attorney, Agent, or Firm-Richard C. Willson, Jr.; Joseph C. Herring; Jack L. Hummel [57] ABSTRACT Carboxy vinyl polymer (CVP) (Carbopol 961) when dissolved with sulfonated alkyl acrylamide polymer, increases screen factor and provides enhanced supplemented recovery of oil.

5 Claims, 2 Drawing Figures THE THICKENER SYSTEM CVP-SAAP SHOWS SYNERGISM PERCENT OF RESIDUAL OIL RECOVERY o SAAP o 25 CVP I00 75 PATENTEB JUL 2 3 I974 SHEET 1 BF '2 THE THICKENER SYSTEM CVP-SAAP SHOWS SYNERGISM O O o O 5 4 3 2 SAAP o CVP I00 Pmmen @5068 SHEET 2 BF 2 THE THICKENER SYSTEM CVP-SAAP SHOWS SCREEN FACTOR SYNERGISM 32 0 (z o it u.

24 2 Lu Lu 5 (n O CVP 0 100 200 SAAP 200 I00 O CONCENTRATION PPM CROSS REFERENCES TO RELATED APPLICATIONS The following cases relate to the same general field as that of the present invention:

U.S. Pat. Nos. 3,507,331 and 3,467,187; Ser. No. 74,336 filed-Sept. 22, 1970 now U.S. Pat. No. 3,677,344; Ser. No. 76,140 filed Sept. 28, 1970 now U.S. Pat. No. 3,724,545; Ser. No. 67,726 filed Aug. 28, 1970 now U.S. Pat. No. 3,670,820; Ser. No. 79,591 filed Oct. 9, 1970 now U.S. Pat. No. 3,692,113; Ser. No. 85,064 filed Oct. 29, 1970 now U.S. Pat. No. 3,684,014; Ser. No. 126,731 filed Mar. 22, 1971 pending; Ser. No. 133,060 filed Apr. 12, 1971 now U.S. Pat. No. 3,746,094; Ser. No. 140,931 filed May 6, 1971 allowed; Ser. No. 209,479 filed Nov. 26, 1971 allowed; Ser. No. 238,143 filed Mar. 24, 1972; Ser. No. 220,910 filed Jan. 26, 1972.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates primarily to wells classified in Class 166 of the United States Patent Office,

monomer is disclosed in Lubrizol Corporations U. S. I

. Pat. No. 3,506,707. 'N-sulfohydrocarbon-substituted acrylamide polymers as viscosity increasing agents for secondary oil recovery are disclosed in Lubrizol Corporations Canadian Patent 864,434.

Carboxy vinyl polymers, (CVP), e.g., B. F. Goodrich Chemical Companys Carbopol, (described in their Service Bulletin GC-36) have been used as viscosityincreasing agents in secondary recovery operations. However, the present invention embodies the discovery that a combination of two agents provides unexpected increase in the efficiency of petroleum recovery, substantially above that which would be expected from an examination of data on the use of either of the polymers alone. The prior art discussed in the aforementioned related applications also has applicability to the SUMMARY OF THE INVENTION This invention relates to a method of improving mobility control of a flooding process by injecting anaqueous solution of CVP and sulfonated alkyl acrylamide polymer (SAAP) into the oil bearing formation. The result of the injection of this aqueous solution is a substantial increase in the screen factor property and also the production of petroleum from subterranean formations.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 compares the supplemented oil recoveries obtained at various compositions of thickener, all used at 500 ppm concentration. The magnitude of the synergism attained with (SAAP) (Lubrizol polymer) in combination with CVP is indicated by the area between the two curves.

FIG. 2 shows the unexpected synergistic improvementin screen factor that is obtained with a thickener formulation comprised of 50 CVP and 50 percent SAAP (Lubrizol polymer) used to push a 0.03 pore vol ume of surfactant slug.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Starting Materials:

By CVP or carboxy vinyl polymer, is meant herein water soluble high molecular weight polymers containing predominantly carboxy vinyl monomer units which can be produced according to the techniques of U.S. Pat. No. 2,798,053, without substantial comonomers.

By sulfonated alkyl acrylamide polymer is meant herein high molecular weight polymers containing predominantly sulfonated alkyl acrylamide monomer units.

The SAAP will preferably have molecular weightsin the range above 0.1 X 10 preferably from 0.5 to 40 X 10 more preferably from 1 X 10 to 15 X 10, and most preferably from 3 X l0 to 10 X 109. Preferably the SAAP will be present in amounts of from about 0.001 to about 10.0, more preferably from 0.01 to aboutlO, and most preferably from 0.02 to about 0.2 weight percent based on the weight of the total solutlon. I

The CVP will preferably have molecular weights above 0. 1 X 10 preferably 0.5 to about 20 X 10 more preferably from 1 to about 15 X 10 and most preferably from 3 X 10 to about 10 X 10.

Preferably, the CVP will be present in amounts from about 0.001 to about 10, more preferably from 0.01 to about 1.0, and most preferably from 0.02 to about 0.2

weight percent based on the total solution.

The solvent for the liquid solutions of the present invention are comprised of water, most preferably consist essentially of connate water, for example, Palestine line water, fresh water, or brackish water. It is preferable that the water contain less than about 300,000, more preferably less than about 10,000, and most preferably less than about 500 parts per million of dissolved solids. The resulting aqueous solution of CVP and SAAP will preferably have viscosity of from about 1.5 to about 1,000 cps, more preferably from about 5 to about 500 cps, and most preferably'from 10 to about cps.

While not necessary to the practice of the present invention, various other ingredients including among others, cellulose derivatives and surfactants, e.g., polyalkyl aryl sulfonate and other conventional displacement fluid additives may be added to the liquid polymer solutions.

Preparation of Liquid Systems:

It will generally be preferable to merely co-mix CVP and the SAAP and then add water while gently stirring to promote dispersion, suspension, and solution. Bubbling a small amount of non-reactive gas, e.g., natural gas, may be used to effect mild stirring. The ingredients will preferably be mixed at an ambient temperature SAAP are prepared by weighing both solids into a bot- 3,825,068 g 3 4 somewhat above room temperature, more preferably summarized in Table 1, the last column of which lists from C. to about 100C., and most preferably from the percent oil recovery based on residual oil remaining C. to about 50C. If desired, a mixing operation can after the preliminary water flood.

be employed in one or more full-type mixers or mixing The synergistic effect of thickened water prepared tees so long as the proportions of the ingredients are 5 from mixed compositions of SAAP and CVP on oil re- B P FllPPQ and.ther ly-ni xeenlieeeum .9990 ar l tietsden F TABLE 1.-SUMMARY OF THICKENED WATER SUPPLEMENTED RECOVERIES Por- Percent of- Total thickened water recovery osity, Permea- Example Run PV, Dery, Percent Number Number cc. cent md. 0 W1 08 Ws Eff. Thiekner PV of 0,.

I 08104 1,098 21.3 784.0 62.7 37.3 37.3 62.7 40.5 500 p.p.m. Lubiizol polymer 1,04 ,7 11 09138 1,013 19.7 927.1 68.8 31.2 39.8 60.2 42.2 500 p.p).m. Lubn'zol polymer (repeat experi- 1,0 67.3

men III 09139 1,094 21.2 702.7 62.5 37.5 36.4 63.6 41.8 250 p.p.m. carboxy vinyl polymer, 250 p.p.m. 0.99 58-9 lubrlzol polymer.

1V 09137 1,092 21.2 780.4 62.5 37.5 36.3 63.7 41.9 500 p.p.m. carboxy vinyl polymer 1,02 39,5

1 3 in. diameter by 4 ft. long Berea sandstone (fired at 825 F.) was first saturated with artificial Henry plant bn'ne (containing 11,000 p.p.m. 01-, 6,500 p.p.m. Na+, 276 p.p.m. Ca 167 p.p.m. My and Henry Crude to an initial 011 saturation (Oi) and initlal'water saturation (We); the core was subsequently flooded to residual saturation (O, and W) and then flood at rat es o1 1.9 to 3.7 ft./day with 0.03 PV of FF-56l slug (petroleum sulfonate slug) followed by up to 1 pore volume of synthetic Palestine Water (containing 400 ppm. NaCl and 55 ppm. 09.012) and the additi n crude recovered and calculated as percent of residual oil in the core before this final flood.

cides and antioxidants can be advantageously added to; MODIFICATIONS OF THE INVENTION preserve the viscosity of the sohmon' It will be understood by those skilled in the art that Screen Factor:

. the relative proportions of the admixture of CVP and Aqueous Solunons of carboxy vmyl polymer and SAAP utilized in the examples herein are merely exemtle, adding deionized water, stirring slowly with a magplary of the relative proportions which may be em' netic bar for several hours until visibl dissolved, and ployed with the present invention or example l then allowing to stand for one day. Testing for screen nearly'loo percent-CV? at the l.eadmg.edge of (115' factor" is done according to Society of Petroleum Engiplacement slug and gradually usmg a h i hlgher neers Paper No. 2867, and the test results are summa- P t g of AP, t0 providea slug whi 18 rized in FIG its leading edge where depletion is most likely to occur. Initial viscosity of the slug may be the same at all points EXAMPLES throughout the slug or may be itself gradually degxamples I through [V are run under identical condicreased until it approaches that of the drive fluid which i tifi ial displaces the slug through the formation.

A 3 inch diameter by 4 foot Berea sandstone cylindri- What is Claimed is: cal core is prepared to simulate a condition at the ter- A Process for the displacement of Oil in an mination of a preliminary secondary water-flood operaaring formation comprising injecting into said formation. This condition is achieved by first saturating the 40 tion an aqueous solution comprised of about 0.001 to core with artificial Henry field water, then partially disabout 10 percent by weight of a water-soluble sulfoplacing this water with Henry field crude oil until satunated alkyl acrylamide polymer and about 0.001 to rated with crude (0,, W and finally water flooding about 10 weight percent water-soluble carboxy vinyl with artiticial Henry water to residual oil (0,) and repolymer based on the weight of the total solution, sidual water (W saturations. wherein said carboxy vinyl polymer is substantially The comparabilities of the examples employing varia homopolymer. ous thickeners insupplemented recovery operations 2, Process according to claim 1 wherein the aqueous are established by the preliminary data On P solution is characterized by a viscosity of from about umes (PV), porosities, permeabilities (ind), initial oil 15 to about 1,000 ti i and Water Saturatiofls 1, 1) residual Oil and Water 3. Process according to claim 2 wherein the aqueous Salutations r and r) after Preparation Simulated solution is characterized by a viscosity of from about 5 water flood with a typical Henry field plant water, and to about 500 centipoises Similar efficiencies of Water flood recovery 4. Process according to claim 2 wherein the aqueous In all experiments Supplemental floods a PV g solution is characterized by a viscosity of from about 10 of a petroleum sulfonate (FF-561) was pushed in the to about 100 Centipoises secondary flooding operation by up to about 1 PV of the particular thickened water. In each example the injection of thickened water was continued to the point vinyl polymer has a molecular weight above 100,000.

atwhich no additional oil was recovered. The data are M M55; i A315 5. Process according to claim 1 wherein the carboxy UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,825,068 Dated 7/23/74 lnventoris) CHARLES J. NORTON ET AL It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 2 line 11: Delete "50 CVP" and insert -50 percent CVP-.

Col. 3-4, Table 1: In headings: Delete "Percent of o w. o w,,

l S S and insert therefor:

- Percent of 1 o w o w Col. 3, line 35: Delete artificial" after "conditions".

Signed and Sealed this Attest:

RUTH C. MASON LUTRELLE F. PARKER Attesting Ojficer Acting Commissioner of Patents and Trademarks Patent No.

Dated 7/23/74 Inventoris) CHARLES J. NORTON ET AL It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 2, line ll:

Col. 3-4, Table 1: In headings:

Col. 3, line 35:

[SEAL] Delete "50 CVP" and insert 50 percent CVP-.

"Percent of o w. o w,,

l S S Delete and insert therefor:

- Percent of i r r-.

Delete artificial" after "conditions".

Attest:

RUTH C. MASON Attesting Officer LUTRELLE F. PARKER Acting Commissioner of Patents and Trademarks 

2. Process according to claim 1 wherein the aqueous solution is characterized by a viscosity of from about 1.5 to about 1,000 centipoises.
 3. Process according to claim 2 wherein the aqueous solution is characterized by a viscosity of from about 5 to about 500 centipoises.
 4. Process according to claim 2 wherein the aqueous solution is characterized by a viscosity of from about 10 to about 100 centipoises.
 5. Process according to claim 1 wherein the carboxy vinyl polymer has a molecular weight above 100,000. 